Zhang Bin, Feng Qibo, You Fengling, Gao Xiaojing. Vibration Measurement System Based on the Crystal BSO[J]. Acta Optica Sinica, 2012, 32(3): 312003
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A high-frequency mirco-vibration measurement system based on the photorefractive crystal is presented. The homodyne interferometer configuration is adopted and the crystal Bi12SiO20 (BSO) is used to record the dynamic holographic signal formed by the interference of the signal beam and the reference beam. Simultaneously, the diffracted reference beam is generated and interferes on the photodetector with the partial signal beam transmitted directly through the crystal. Time-based signals of photocurrent which is proportional to the vibration displacement are obtained. The factors that affect diffraction efficiency have been investigated such as intensity ratio of the reference beam and the signal beam, the angle between the above two beams. Another quarter-wave plate is used in the reference beam path to improve the measuring sensitivity without electric field on the crystal. A piezoelectric ceramic is used as the target and the detected frequency by this system exactly corresponds to the predetermined frequency from 0.5 kHz to 90 kHz.